<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script>
			function call(){
				var text = document.getElementById("ss")
				var val = text.value;
				try{
					var result = eval(val)
					text.value = result
				}catch(e){
					console.log(e)
				}
			}
		</script>
	</head>
	<body>
		<input type="text" id="ss">
		<input type="button" value="=" onclick="call()">
	</body>
</html>